Abstract : The study found that, under laboratory conditions, the concentrations of solvent vapors in the air can be predicted mathematically with good accuracy. Extending the use of the model to industrial operations, it was shown that the emissions from an actual vapor degreaser can also be estimated. The model can therefore, be applied to optimize ventilation design, optimize degreaser design to achieve maximum efficiency with minimum emissions and optimize existing degreaser operating procedures. The results of the field sampling performed in conjunction with this study revealed a definite requirement to have a cover installed on all vapor degreasers. Such an installation will not only protect the worker at or near the degreaser, it will significantly reduce solvent usage. (Modified author abstract)